MATLAB: How to please reduce the code running time

longtimeruntime

Dear All, I wrote this code to analyze my text data, each time I run this code it takes exactly 22 minutes to finish ! which is very long time, since I am new on MATLAB I still don't know the tricks to minimize running time, will any body please give me some ideas regarding this code? Thank you MATLAB Community

clear;
  clc;
    directory=dir('*.Y07');
    count=0;
    for K = 1 : length(directory)
        filename = directory(K).name;
        fileID = fopen(filename,'r');
        formatSpec = '%s';
        A_cell = textscan(fileID,formatSpec);
        A=char(A_cell{1,1}{:,:});
        A(find(isnan(A)))=0;
        [rows,columns]=size(A);
        if columns~=105 
     ArrayTemp=zeros(rows,105);
     ArrayTemp(1:rows,1:columns)=A;
     A=ArrayTemp;
     A=char(A);
     A(isspace(A)) = '0';
    end
        x1=filename;
        xtr=strcat('C:\Users\maa285\Desktop\New folder (2)\',x1);
        fid = fopen( xtr, 'wt' );
        Record_Type = A(:,1:1);
        FibsCode = A(:,2:3);
        StationID = A(:,4:9);
        Direction_Of_Travel = A(:,10:10);
        Lane_Of_Travel = A(:,11:11);
        Year_of_Data = A(:,12:13);
        Month_of_Data = A(:,14:15);
        Day_of_Data = A(:,16:17);
        Hour_of_Data = A(:,18:19);
        Vehicle_Class = A(:,20:21);
        Open = A(:,22:24);
        Total_Weight_of_vehicle = A(:,25:28);
        Number_of_axles = A(:,29:30);
        A_Axle_Weight = A(:,31:33);
        A_B_Axle_spacing = A(:,34:36);
        B_Axle_Weight = A(:,37:39);
        B_C_Axle_spacing = A(:,40:42);
        C_Axle_Weight = A(:,43:45);
        C_D_Axle_spacing = A(:,46:48);
        D_Axle_Weight = A(:,49:51);
        D_E_Axle_spacing = A(:,52:54);
        E_Axle_Weight = A(:,55:57);
        E_F_Axle_spacing = A(:,58:60);
        F_Axle_Weight = A(:,61:63);
        F_G_Axle_spacing= A(:,64:66);
        G_Axle_Weight = A(:,67:69);
        G_H_Axle_spacing = A(:,70:72);
        H_Axle_Weight = A(:,73:75);
        H_I_Axle_spacing = A(:,76:78);
        I_Axle_Weight= A(:,79:81);
        I_J_Axle_spacing = A(:,82:84);
        J_Axle_Weight = A(:,85:87);
        J_K_Axle_spacing= A(:,88:90);
        K_Axle_Weight = A(:,91:93);
        K_L_Axle_spacing = A(:,94:96);
        L_Axle_Weight = A(:,97:99);
        L_M_Axle_spacing = A(:,100:102);
        M_Axle_Weight = A(:,103:105);
        %This is to convert the string to numbers so it can show the output:
        Ans_1=str2num(Record_Type);
        fprintf(fid,Record_Type);
        Ans_2=str2num(FibsCode);
        fprintf(fid,FibsCode);
        Ans_3=str2num(StationID);
        fprintf(fid,StationID);
        Ans_4=str2num(Direction_Of_Travel);
        fprintf(fid,Direction_Of_Travel);
        Ans_5=str2num(Lane_Of_Travel);
        fprintf(fid,Lane_Of_Travel);
        Ans_6=str2num(Year_of_Data);
        fprintf(fid,Year_of_Data);
        Ans_7=str2num(Month_of_Data);
        fprintf(fid,Month_of_Data);
        Ans_8=str2num(Day_of_Data);
        fprintf(fid,Day_of_Data);
        Ans_9=str2num(Hour_of_Data);
        fprintf(fid,Hour_of_Data);
        Ans_10=str2num(Vehicle_Class);
        fprintf(fid,Vehicle_Class);
        Ans_11=str2num(Open);
        fprintf(fid,Open);
        Ans_12=str2num(Total_Weight_of_vehicle);
        fprintf(fid,Total_Weight_of_vehicle);
        Ans_13=str2num(Number_of_axles);
        fprintf(fid,Number_of_axles);
        Ans_14=str2num(A_Axle_Weight);
        fprintf(fid,A_Axle_Weight);
        Ans_15=str2num(A_B_Axle_spacing);
        fprintf(fid,A_B_Axle_spacing);
        Ans_16=str2num(B_Axle_Weight);
        fprintf(fid,B_Axle_Weight);
        Ans_17=str2num(B_C_Axle_spacing);
        fprintf(fid,B_C_Axle_spacing);
        Ans_18=str2num(C_Axle_Weight);
        fprintf(fid,C_Axle_Weight);
        Ans_19=str2num(C_D_Axle_spacing);
        fprintf(fid,C_D_Axle_spacing);
        Ans_20=str2num(D_Axle_Weight);
        fprintf(fid,D_Axle_Weight);
        Ans_21=str2num(D_E_Axle_spacing);
        fprintf(fid,D_E_Axle_spacing);
        Ans_22=str2num(E_Axle_Weight);
        fprintf(fid,E_Axle_Weight);
        Ans_23=str2num(E_F_Axle_spacing);
        fprintf(fid,E_F_Axle_spacing);
        Ans_24=str2num(F_Axle_Weight);
        fprintf(fid,F_Axle_Weight);
        Ans_25=str2num(F_G_Axle_spacing);
        fprintf(fid,F_G_Axle_spacing);
        Ans_26=str2num(G_Axle_Weight);
        fprintf(fid,G_Axle_Weight);
        Ans_27=str2num(G_H_Axle_spacing);
        fprintf(fid,G_H_Axle_spacing);
        Ans_28=str2num(H_Axle_Weight);
        fprintf(fid,H_Axle_Weight);
        Ans_29=str2num(H_I_Axle_spacing);
        fprintf(fid,H_I_Axle_spacing);
        Ans_30=str2num(I_Axle_Weight);
        fprintf(fid,I_Axle_Weight);
        Ans_31=str2num(I_J_Axle_spacing);
        fprintf(fid,I_J_Axle_spacing);
        Ans_32=str2num(J_Axle_Weight);
        fprintf(fid,J_Axle_Weight);
        Ans_33=str2num(J_K_Axle_spacing);
        fprintf(fid,J_K_Axle_spacing);
        Ans_34=str2num(K_Axle_Weight);
        fprintf(fid,K_Axle_Weight);
        Ans_35=str2num(K_L_Axle_spacing);
        fprintf(fid,K_L_Axle_spacing);
        Ans_36=str2num(L_Axle_Weight);
        fprintf(fid,L_Axle_Weight);
        Ans_37=str2num(L_M_Axle_spacing);
        fprintf(fid,L_M_Axle_spacing);
        Ans_38=str2num(M_Axle_Weight);
        fprintf(fid,M_Axle_Weight);
        %to establish a new arrays for the date:
        monthvar = Month_of_Data;
        dayvar = Day_of_Data;
        yearvar = Year_of_Data;
        datevar = strcat(num2str(monthvar),'/',num2str(dayvar),'/',num2str(yearvar));
    %     DayNumber = weekday(datevar);
        [DayNumber,DayName] = weekday(datevar);
        %%to return the separated vectors into one new matrix with usable data:
        all=[Ans_2,Ans_2,Ans_3,Ans_4,Ans_5,Ans_6,Ans_7,Ans_8,Ans_9,Ans_10,DayNumber,Ans_12,Ans_13,Ans_14,Ans_15,Ans_16,Ans_17,Ans_18,Ans_19,Ans_20,Ans_21,Ans_22,Ans_23,Ans_24,Ans_25,Ans_26,Ans_27,Ans_28,Ans_29,Ans_30,Ans_31,Ans_32,Ans_33,Ans_34,Ans_35,Ans_36,Ans_37,Ans_38];
    %     all(isspace(all)) = '0';
        %now select each class data out of the original data A.
        VehClass = Ans_10;
        Class9_data = all(VehClass == 9, :);
        count=count+1;
    end

Best Answer

You are using fprintf() with no format specifier, passing in what looks to be character strings. The character strings are going to be interpreted as being format strings. That will mostly result in the character strings being output. However, they will be output with no spaces between them and no delimiter.

You can improve performance by calling fprintf() fewer times, such as

fprintf(fid, '%s %s %s %s %s', H_Axle_Weight, H_I_Axle_Weight, I_Axle_Weight, I_J_Axle_Weight)

Related Solutions

MATLAB: How to use the str2num for the whole array at once

"I have older than what Mr Walter said" Thus the old way

Read the file and convert the content to an old time string array, str

    fid = fopen( 'NewTextDocument.txt' );
    cac = textscan( fid, '%s', 'Delimiter', '\n' );
    fclose( fid );
    str = char( cac{1} );
    str( str==' ' ) = '0';

Inspect str

>> whos str
  Name       Size             Bytes  Class    Attributes
  str       50x105            10500  char

and

>> str(1,:)
  ans = W39000779310707010002000001802010029008000000000000000000000000000000000000000000000000000000000000000000

Now you have a string array with the width of the longest row. The function, char, padded with space, which I replaced by the character '0'. (I padded one line of the text file with "0" up till the column 105.)

Now convert columns of the character array to numerical column vectors

Vehicle_Class = str2num( str(:,20:21) );
D_Axle_Weight = str2num( str(:,49:51) );

and inspect the result

>> whos Vehicle_Class D_Axle_Weight
  Name                Size            Bytes  Class     Attributes
  D_Axle_Weight      50x1               400  double              
  Vehicle_Class      50x1               400  double

With these pieces of code I think you can make your script work.

MATLAB: Loading .tab in loop, varying header length and number of columns

This imports the requested three columns of data from your sample files, ignoring everything before the */ line. It uses the data header to identify which columns to import.

H = {'Date/Time','Latitude','Longitude'};
F = {       '%s',      '%f',       '%f'};
D = 'data_Matlab_help'; % folder where the files are saved.
S = dir(fullfile(D,'*.tab'));
C = cell(1,numel(S));   % preallocate output cell array.
for k = 1:numel(S)
    [fid,msg] = fopen(fullfile(D,S(k).name),'rt');
    assert(fid>=3,msg)
    str = '';
    while ~strcmp(str,'*/')
        str = fgetl(fid);
    end
    str = fgetl(fid); % read data header line.
    hdr = regexp(str,'\t','split'); % split data header at tabs.
    fmt = repmat({'%*s'},1,numel(hdr)); % define format strings.
    [ids,idz] = ismember(hdr,H); % identify time & Lat & Long.
    fmt(ids) = F(idz(ids));      % replace format strings for time & Lat & Long.
    C{k} = textscan(fid,[fmt{:}],'Delimiter','\t'); % read data.
    fclose(fid);
end

Each cell of C contains the data from one file. With that cell the first cell contains the date/time, the second the Lat, the third the Long. You can check this easily:

>> C{1}{1}(1:10) % first ten dates of first file.
ans = 
    '1905-06-17T00:00'
    '1905-06-17T00:00'
    '1905-06-17T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
    '1957-11-20T00:00'
>> C{1}{2}(1:10) % first ten Latitudes of first file.
ans =
                      79.9
                      79.9
                      79.9
                      70.5
                      70.5
                      70.5
                      70.5
                      70.5
                      70.5
                      70.5
>> C{1}{3}(1:10) % first ten Longitudes of first file.
ans =
                     16.92
                     16.92
                     16.92
                     33.45
                     33.45
                     33.45
                     33.45
                     33.45
                     33.45
                     33.45

Best Answer

Related Solutions

MATLAB: How to use the str2num for the whole array at once

MATLAB: Loading .tab in loop, varying header length and number of columns

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